linkRadius property
The radius of the link arc. If not set, series renders a semi-circle
between the nodes, except when overflowing the edge of the plot area,
in which case an arc touching the edge is rendered. If linkRadius
is set, an arc extending to the given value is rendered.
API Docs: https://api.highcharts.com/highcharts/series.arcdiagram.linkRadius
Implementation
double? linkRadius;